Here are opinions from another novice, so take 'em with a grain of salt.

(1)
If you have N computers mining, then you want:
N accounts in the miners section on all computers -and-
N accounts in the witnesses section on one (and only one) computer; preferably the most stable.

(2)
I don't know the best places, but I use steemd.com/@[userid] and steemstats.com

(3)
Yes, I believe so, although I haven't powered down yet, so I could be misunderstanding something.

(4)
Yes. Speed of your processor, number of threads, sufficient memory, network latency, and numbers of competing miners are the factors I'm aware of.

(5)
With about 27k hash power on 3 computers, my son and I have been getting about 11-14 blocks per day until the last few days. Starting last Thursday, it has been tailing off, and one miner seems to be basically dominating the queue again today. It remains to be seen how/if this will be addressed.

(6)
Lots of blocks and the absence of mining pools. Also, the two year withdrawal period makes it unattractive to people with enough hash power to get significant returns from other coins.

(7)
Not yet. I believe it's set up to make mining pools difficult because it requires private keys.